In fact Son's propensity to spend big has presumably prompted the cut. He has told the Japanese news service, Nikkei, that he's going to invest US$16 billion - most of it on extra base stations on Sprint's network - over the next two years: $8 billion for each of the next two years with more spending to come after that.

That alone would make Softbank a global big spender, but Son's plan is to grind more bang for his Yen by joint infrastructure and handset buying through combining Softbank Japan and Sprint's purchasing.

Far from parachuting in Japanese managers and workers (a ridiculous accusation made during the cut and thrust of Son's takeover), he's going to stick with Sprint CEO Dan Hesse and what looks like the core of the existing Sprint board. If there is any executive traffic post this deal, my guess is that it will just as likely involve US IT executives parachuted into Japan as the other way around.

Mr Son's two companies are also setting up a joint R&D centre in California this year to work on hardware and software - Son, it must be understood, comes from the IT side of the business and no doubt sees Silicon Valley as a valuable resource he can now draw on to energise both his mobile properties. The centre is expected to house at least 1000 engineers.

No surprise that Mr Son says he's going to continue with Sprint's 'unlimited' data pricing and has some new ideas up his sleeve.